Remove simple redundant return statement for Scala methods/functions:

-) Only change simple return statements at the end of method
-) Ignore the complex if-else check
-) Ignore the ones inside synchronized
Merge branch 'master' into remove_simpleredundantreturn_scala
Fix accidental comment modification.
Address code review concerns and comments.
Disable shuffle file consolidation by default
Merge pull request #395 from hsaputra/remove_simpleredundantreturn_scala

Remove simple redundant return statements for Scala methods/functions

Remove simple redundant return statements for Scala methods/functions:

-) Only change simple return statements at the end of method
-) Ignore the complex if-else check
-) Ignore the ones inside synchronized
-) Add small changes to making var to val if possible and remove () for simple get

This hopefully makes the review simpler =)

Pass compile and tests.
Merge pull request #399 from pwendell/consolidate-off

Disable shuffle file consolidation by default

After running various performance tests for the 0.9 release, this still seems to have performance issues even on XFS. So let's keep this off-by-default for 0.9 and users can experiment with it depending on their disk configurations.